Brazing solder



Patented Apr. 18, i933 UNITED STATES PATENT OFFICE l AUG-UST M. DINKLER, F WATEBBUBY, AND CYRIL STANLEY SMITH, 0F CHESHIBE,

CONNECTICUT, ASSIGENORS TO THE AMERICAN BRASS COMPANY, OF WATEBBURYL CONNECTICUT, A CORPORATION 0F CONNECTICUT `naazINc somma application ma August e, 1932. serial 1in. 628,006.

This invention relates to alloys and more and welding purposes, and has for an ob'ect the production pf a low melting point a loy for. use as brazlng solder. Brazing solder customarily employed consists of an alloy of approximately e ual proportions of copper and zinc, and me ts at about 880". C. A series of alloys which finds some application where a low meltin point solder is 'required is the copper-phosp crus series, in which the alloy of lowest melting point contains about 8.4 percent phos horus and melts at 714 C. We have found t at by replacing Fart of the copper by an equivalent amount o zinc up to about 32.5 percent, alloys of essentiallyl the same characteristics as the binary copperphosphorus alloys are obtained, exce t that the melting point is decreased and the uidity somewhat improved while the cost of the alloy is reduced. Beyond about 32.5 percent zinc the melting point progressively increases, on account of the appearanceA of the so-called beta phase of the copper-zinc system. Additions of hosphorus are less effective'A in reducing t e'melting point of alloys containing thebeta phase than they are 'in alloys in which alpha 1s the primary constituent for a phosphide containing zinc and having a high me ting point occurs in thls portion of the diagram.- The alloy of lowest Vmelting point in the series containing less than 55 percent zinc occurs at about the composition 25-32.5(percent zinc, 6.5-6.0 percent phosphorus, an 61.5-68.5 percent copper. These alloys melt completely at about 695 i C., a figure which should be compared with 714 C., the melting point of the binary copper-phosphorus eutectic at'SA percent phosphorus. y

The melting point of the useful portion of the series according to our researches is shown in the figure of the drawing, the meltints being accurate to within about 10 The line AB represents the course of the binary eutectic between alpha and Cual across the solid model of the ternary diagram, the point B representing the ternar eutectic formed by t e reaction of liqui CmP, alpha, and a zinc-rich phosphidev of unknown composition. It is obvious from the \d1iagram\ that substantially the same v melting point is obtained by any alloys along AB, although the temperature of melting lrihes somewhat rapidly along BC whichrepresents the binary eutectic between the alpha phase and the zinc-containing phosphide, and even more rapidly along CE or CD. On the basis of melting point alone, the alloy B is the most satisfactory solder but vsubstantially the same results are obtainable with any alloy alongr AB and We have obtained particularly good results with the alloys containing approximately 27.5 percent zinc, 6.2 percent phosphor-us.

The brittleness of alloys containing less than percent zinc is a function of the phosphorus content, and alloys of lower phosphorus content than the eutectic are often advisable 'where a stronger and more ductile joint isl required. We prefer, however, to limit the composition to a point where the melting point, as shown in the figure of the drawing is less than 850 C., the amount of phosphorus being greater than 2.5 percent. Although the alloys are malleable in certain ran es of com osition and may be hot worked to e form o wire rod, sheet or strip, other alloys are too brittle for this to be done, but any of the alloys may be used in the granulated condition.

No iiux is needed if the surface of the metal Y We have obtained satisfaciron phosphides between the steel surface and the body of the solder renders the joints very brittle.

On account of the high fiuidity and low melting point the alloys arefsuitable for die castings or permanent moldcastings where accuracy ofsh ,is desired and high ductility is not of importance.

Having thus set forth the nature of our invention, what we claim is 6 1. A n allow composed of a substantial amount of phosphorus above 2.50Uand up to 10 percent, from 5 to 50 percent zinc, the

balance being principali co per.

2. An alloy compose o approximately l0 2532.5 percent zinc, 6.5-6.0 percent phosphorus, {S15-68.5 percent co per.

3. An alloy composed o approximately 27.5 percent zinc, and 6.2 percent phosphorus, the balance being principally copper.

l5 4. An alloy composed of `approximately 32.5 percent zinc 6.1 percent phosphorus, the

balance being principali copper.

In testimony whereo we ax our signatures.. 20 f AUGUST M. DINKLER. Y

CYRIL STANLEY SMITH.

clamrIcAmcF common. marne-1,904,360. April 1s, 1939..`

'AUGUST M. DINKLER, ET Ax..

K It n hefehyrniieathnerror man irritable-md amitiee-ion of the above patentrequiringy correction aa fol'low: Page 2, line 5', claim l, me *f'lllnw read ,lllyz llld `that the said Letters Patent should be read with thlccrrecton therein that the 4same ma conform to the d this om, h y n yY p recor of the calc in Signed and sealed this 16th day of October, D. 1934.

Les! ie Frazer p (Seal) Actlnoulnieaioner of Patents. j

Having thus set forth the nature of our invention, what we claim is ow composed of a substantial amount of phosphorus above 2.50Uand up to 10 percent, from 5 to 50 percent zinc, the

balance being principali co per.

2. An alloy compose o approximately l0 2532.5 percent zinc, 6.5-6.0 percent phosphorus, 61.5-68.5 percent co per.

3. An alloy composed o approximately 27.5 percent zinc, and 6.2 percent phosphorus, the balance being principally copper.

l5 4. An alloy composed of approximately 32.5 percent zinc 6.1 percent phosphorus, the

balance being principali copper.

tures..

(sul) In testimony whereo we aix our signa- AUGUST M DINKLER. Y CYRIL STANLEY SMITH.

cERrxricAmcr common.

menno.- .Loa-seo. April 1s, 1933. p

'AUGUST M. DINKLER, ET Ax..

K It n hefehyrziieathnerror ippeir'a indichi-md @widen-ion of the above patentrequiringy correction ae fol'low: Page 2, line 5', claim l, me *fellow read ,lllyz llld `that the said Letters Patent should be read with thia"ccrrection therein that the 4same ma conform to the d this om, h y n yY p recor of the cale in Signed and sealed this 16th day of October, D. 1934.

Leslie Frazer Actlnonlnissioner of Patente. j 

